From b98297c416953edfda0ead66ac157632df08247b Mon Sep 17 00:00:00 2001
From: Karl Gaissmaier <karl.gaissmaier@uni-ulm.de>
Date: Fri, 20 Jan 2023 15:17:27 +0100
Subject: [PATCH] remove Size() from API

---
 README.md     |  1 -
 bench_test.go | 15 ---------------
 helpers.go    | 17 ++++-------------
 treap_test.go | 20 ++++++++++++--------
 4 files changed, 16 insertions(+), 37 deletions(-)

diff --git a/README.md b/README.md
index b09d680..496c859 100644
--- a/README.md
+++ b/README.md
@@ -103,7 +103,6 @@ type Interface[T any] interface {
   func (t Tree[T]) Visit(start, stop T, visitFn func(item T) bool)
   func (t Tree[T]) Fprint(w io.Writer) error
   func (t Tree[T]) String() string
-  func (t Tree[T]) Size() int
   func (t Tree[T]) Min() (min T)
   func (t Tree[T]) Max() (max T)
 ```
diff --git a/bench_test.go b/bench_test.go
index 50ea356..f94d30b 100644
--- a/bench_test.go
+++ b/bench_test.go
@@ -248,21 +248,6 @@ func BenchmarkIntersections(b *testing.B) {
 	}
 }
 
-func BenchmarkSize(b *testing.B) {
-	for n := 100; n <= 1_000_000; n *= 10 {
-		ivals := generateIvals(n)
-		tree := interval.NewTree(ivals...)
-		name := "In" + intMap[n]
-
-		b.Run(name, func(b *testing.B) {
-			b.ResetTimer()
-			for n := 0; n < b.N; n++ {
-				_ = tree.Size()
-			}
-		})
-	}
-}
-
 func BenchmarkMin(b *testing.B) {
 	for n := 100; n <= 1_000_000; n *= 10 {
 		ivals := generateIvals(n)
diff --git a/helpers.go b/helpers.go
index 2d31fb9..9c9d585 100644
--- a/helpers.go
+++ b/helpers.go
@@ -298,13 +298,14 @@ func (n *node[T]) pcmForNode(pcm parentChildsMap[T]) parentChildsMap[T] {
 // 0.x.y. In future versions this will be removed without increasing the main
 // semantic version, so please do not rely on it for now.
 //
-func (t Tree[T]) Statistics() (maxDepth int, average, deviation float64) {
+func (t Tree[T]) Statistics() (size int, maxDepth int, average, deviation float64) {
 	// key is depth, value is the sum of nodes with this depth
 	depths := make(map[int]int)
 
-	// get the depths
+	// get the depths, sum up the size
 	t.root.traverse(inorder, 0, func(n *node[T], depth int) bool {
 		depths[depth] += 1
+		size += 1
 		return true
 	})
 
@@ -326,7 +327,7 @@ func (t Tree[T]) Statistics() (maxDepth int, average, deviation float64) {
 	variance = variance / float64(sum)
 	deviation = math.Sqrt(variance)
 
-	return maxDepth, average, deviation
+	return size, maxDepth, average, deviation
 }
 
 // Min returns the min item in tree.
@@ -355,16 +356,6 @@ func (t Tree[T]) Max() (max T) {
 	return n.item
 }
 
-// Size returns the number of items in tree.
-func (t Tree[T]) Size() int {
-	size := 0
-	t.root.traverse(inorder, 0, func(k *node[T], _ int) bool {
-		size++
-		return true
-	})
-	return size
-}
-
 // Visit traverses the tree with item >= start to item <= stop in ascending order,
 // or if start > stop, then the order is reversed. The visit function is called for each item.
 //
diff --git a/treap_test.go b/treap_test.go
index cc1ff7c..721402b 100644
--- a/treap_test.go
+++ b/treap_test.go
@@ -92,12 +92,12 @@ func TestNewTree(t *testing.T) {
 		t.Errorf("CoverSCP(), got: %v, want: false", ok)
 	}
 
-	if s := zeroTree.Insert(zeroItem); s.Size() != 1 {
-		t.Errorf("Insert(), got: %v, want: 1", s.Size())
+	if size, _, _, _ := zeroTree.Insert(zeroItem).Statistics(); size != 1 {
+		t.Errorf("Insert(), got: %v, want: 1", size)
 	}
 
-	if s := zeroTree.Clone(); s.Size() != 0 {
-		t.Errorf("Clone(), got: %v, want: 0", s.Size())
+	if size, _, _, _ := zeroTree.Clone().Statistics(); size != 0 {
+		t.Errorf("Clone(), got: %v, want: 0", size)
 	}
 
 	if s := zeroTree.CoveredBy(zeroItem); s != nil {
@@ -172,8 +172,8 @@ func TestTreeWithDups(t *testing.T) {
 	}
 
 	tree := interval.NewTree(is...)
-	if s := tree.Size(); s != 5 {
-		t.Errorf("Size() = %v, want 5", s)
+	if size, _, _, _ := tree.Statistics(); size != 5 {
+		t.Errorf("Size() = %v, want 5", size)
 	}
 
 	asStr := `▼
@@ -676,7 +676,7 @@ func TestVisit(t *testing.T) {
 		return true
 	})
 
-	want = tree.Size()
+	want, _, _, _ = tree.Statistics()
 	if len(collect) != want {
 		t.Fatalf("Visit() descending, want: %d  got: %v, %v", want, len(collect), collect)
 	}
@@ -790,7 +790,11 @@ func TestStatistics(t *testing.T) {
 		t.Run(count, func(t *testing.T) {
 			tree := interval.NewTree(generateIvals(n)...)
 
-			_, averageDepth, deviation := tree.Statistics()
+			size, _, averageDepth, deviation := tree.Statistics()
+			if size != n {
+				t.Fatalf("size, got: %d, want: %d", size, n)
+			}
+
 			t.Logf("stats: n=%d, averageDepth=%.4g, deviation=%.4g\n", n, averageDepth, deviation)
 
 			maxAverageDepth := 2 * math.Log2(float64(n))